"Neuroticism was an especially strong predictor of the particularly pernicious state of developing both anxiety and depressive disorders," said Richard Zinbarg, professor of psychology in the Weinberg College of Arts and Sciences at the Northwestern University.

Earlier research has shown that neuroticism is associated with substance abuse, mood and anxiety disorders but hadn't tested whether these associations are comparable in strength.

But the Northwestern and University of California-Los Angeles study found for the first time that neuroticism predicts mood and anxiety disorders more strongly.

The study included 547 participants recruited as high school juniors at two Chicago and Los Angeles high schools.

High schools students were given a questionnaire on neuroticism that determined their standing on that personality trait.

"We can identify those kids that we should be targeting -- that's the first implication," Zinbarg said.

The goal would be to design a prevention that would not only prevent depression or anxiety disorders but reduce risks for both, given that they have got a common risk factor.

The team did study substance use and found that neuroticism was not as strong a predictor of substance use disorders as anxiety disorders and depression.

"The results strongly suggest that neuroticism is more sensitive to threat than emotional reactivity writ large," Zinbarg noted in a paper forthcoming in the journal Clinical Psychological Science.